This invention relates to an antenna arrangement and to an antenna array comprising the arrangement, including a collapsible arrangement and array.
In radio direction finding applications, it is known to use loop-based Watson-Watt arrays or Adcock arrays. Loop-based Watson-Watt arrays are generally perceived to be inferior to Adcock arrays, mainly due to the inherent sensitivity of loop-based radiators to horizontal polarization (HP), which causes unavoidable estimation errors when the incoming wave is not purely vertically polarized (VP), and secondly, due to inaccuracy when waves are incident from high angles of elevation. These problems often come to the fore at low frequencies (in the HF band) with sky wave propagation, but not ground wave propagation. At higher frequencies, however, ground waves support appreciable HP and loops then suffer accuracy degradation due to cross-polarization making them unpopular for use in the upper HF and VHF regions and above. Adcock arrays suffer a disadvantage over loop elements from a sensitivity point of view when the arrays are small in size, which makes Adcock arrays less desirable for use in small tactical systems that are expected to work below 100 MHz.